Envelopes, parcels, and other packages containing items may be shipped using postal carriers. In the past, most carriers calculated the fee to charge for the transportation of certain items, such as letters and envelopes, on the weight of the item and its container, as well as the distance the item was to be transported. Accordingly, the fee charged for the transportation of a letter or envelope would generally be based solely on the distance to be traveled and the weight of the item, regardless of the envelope's size.
Previous systems were designed to assist customers in estimating the costs associated with transporting the item simply by weighing the item. Other systems allow a customer to estimate the total costs of transportation based on the item's weight along with the originating and destination postal or zip codes.
Some carriers have begun to include size or dimensional requirements as a factor in the calculation of the transportation fees for items previously calculated solely on weight. These and other carriers may require that the dimensions of a letter or envelope fall within a specific range in order to qualify for certain rates that correspond with that range. If the length, width, and/or thickness of an envelope exceeds the maximum allowable length, width, or thickness for a class of mail, the fee required to transport the letter will increase to the rate associated with the class of mail corresponding to the dimensional range in which the letter will be categorized. In some cases, if the dimensions of a letter or envelope exceed the maximum allowable dimensions for letters, the item may be reclassified as a package for which the associated transportation fee will be greater.
In other situations, a letter may fail to qualify for a less expensive class due to the manner in which it has been folded. Folding the letter in a different manner, however, may allow it to qualify for the less expensive class. For instance, if a postal carrier has established a maximum thickness for a class of mail, folding a multi-page letter several times may cause the thickness of the enclosing envelope to exceed the maximum allowable thickness for that class. Instead, folding the letter in halves or not at all and placing the letter in a wider and/or longer envelope may allow the letter to qualify for the less expensive class. Prior measurement devices, however, do not allow the user to determine that different arrangements would be more cost-effective.